From abc586a6d4a72dc1cbba7c4b1accb585337cdcb7 Mon Sep 17 00:00:00 2001
From: David Capello <davidcapello@gmail.com>
Date: Wed, 23 Nov 2016 14:08:34 -0300
Subject: [PATCH] Fix bug on macOS scrolling frames w/mouse wheel in the wrong
 direction

Sometimes macOS returns us a delta of 0.0, so we should not move through
frames in that case.
---
 .../ui/editor/state_with_wheel_behavior.cpp   | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/src/app/ui/editor/state_with_wheel_behavior.cpp b/src/app/ui/editor/state_with_wheel_behavior.cpp
index 5fee94fb8..dff24b784 100644
--- a/src/app/ui/editor/state_with_wheel_behavior.cpp
+++ b/src/app/ui/editor/state_with_wheel_behavior.cpp
@@ -113,15 +113,18 @@ bool StateWithWheelBehavior::onMouseWheel(Editor* editor, MouseMessage* msg)
       }
       break;
 
-    case WHEEL_FRAME:
-      {
-        Command* command = CommandsModule::instance()->getCommandByName
-          ((dz < 0.0) ? CommandId::GotoNextFrame:
-                        CommandId::GotoPreviousFrame);
-        if (command)
-          UIContext::instance()->executeCommand(command);
-      }
+    case WHEEL_FRAME: {
+      Command* command = nullptr;
+
+      if (dz < 0.0)
+        command = CommandsModule::instance()->getCommandByName(CommandId::GotoNextFrame);
+      else if (dz > 0.0)
+        command = CommandsModule::instance()->getCommandByName(CommandId::GotoPreviousFrame);
+
+      if (command)
+        UIContext::instance()->executeCommand(command);
       break;
+    }
 
     case WHEEL_ZOOM: {
       render::Zoom zoom = editor->zoom();